Apple's latest OS X version amps up the iOS integration, but offers much more for business and personal use

After five months of anticipation, OS X Mountain Lion is now available. The $20 OS upgrade for Intel-based Macs goes a long way to bringing iOS applications and capabilities into the Mac OS, and it adds a variety of new capabilities aimed specifically at computer users. Many changes are under the hood, such as enhanced security capabilities to protect the kernel during startup, and several add up to a better experience, such as scroll bars that widen automatically as you use them.

I've spent five months poring over the beta for my forthcoming book, "OS X Mountain Lion Bible." Here are my picks for the top 25 new or improved features to look for.

Introduced in the third-gen iPad, voice transcription arrives on the Mac in OS X Mountain Lion. Using a keyboard shortcut or menu option, you can speak text in any text field or text window and have Apple's servers translate your dictation into text that is then placed in your field or document. Supported languages are English, French, German, Japanese, and Spanish.

In the last year, the Mac has seen its first serious malware attacks, using third-party conduits such as Java. Apple loves people to think that malware is a Windows problem, but it's been forced to add antimalware capabilities to OS X Lion and enhance them in OS X Mountain Lion with the new Gatekeeper facility.

By default, only apps purchased from the Mac App Store install in OS X Mountain Lion. But you can let third-party apps with a valid Apple developer ID install, no matter where obtained. And you can disable Gatekeeper -- including for just an individual installation that you trust via a contextual menu option. The idea is that even if malware comes into your Mac, it can't install itself without your permission.

Another iOS inspiration, developers can iCloud-enable their apps to store and retrieve documents directly from Apple's iCloud service for access on both Macs and iOS devices. As in iOS, an app sees only its files, though you can easily move or copy them among other apps and between the Finder on your Macs, where all apps can see them (unlike in iOS).

There is a gotcha: Only apps sold via the Mac App Store may use the iCloud Documents APIs. Preview and TextEdit are among the built-in apps that support iCloud Documents; Apple's iWork suite has been revved to do so as well.

Yet another iOS derivation, the Notification Center provides a single tray that lists all recent alerts for the apps you specify, as well as for notification-enabled websites and Apple services such as Software Update. Several styles of alerts are available, so you can customize the level of intrusion per app, as well as disable notifications.

There's also an option to temporarily disable all notificatlons, and OS X Mountain Lion is smart enough to automatically disable notifications when you are making a Keynote presentation or streaming video to your TV via iTunes or through AirPlay mirroring.

Here's a feature that debuted in OS X before iOS: In Mountain Lion, a new iCloud Tabs popover in Safari 6.0 lets you access recently and currently open browser tabs in any Mac that has the same Apple ID, so you can pick up where you left off as you move from machine to machine. When iOS 6 ships this fall, its Safari browser will also participate, so your iCloud tabs will work across iOS and OS X.

Safari 6.0 also unifies the address (URL) and search bars, À la Google Chrome, so searching and entering URLs are now the same thing. As you type in Address and Search bar, suggested sites display below it.

Apple introduced the Reading List capability more than a year ago to Safari, letting you save Web pages to be read later. Once read, they disappear from the Reading List. In OS X Mountain Lion, Safari now saves the HTML files so that you can read your saved Web pages when not connected to the Internet, such as on a plane or train. (iOS 6 will gain this feature as well.)

It's smart enough to save all pages in a multipage article, not just the page you were on when adding it to the Reading List.

Back to iOS-inspired changes: OS X Mountain Lion now provides a standard facility to share content in applications such as Safari and QuickTime Pro via Twitter, Facebook, Vimeo, other social sites, email, iMessage (the new chat service), and AirDrop (the zero-configuration peer-to-peer Wi-Fi transfer protocol introduced in OS X Lion).

Facebook and Twitter integration go even deeper: Both update your contacts (if you permit them) for your friends and the people you follow, and both can be updated (meaning tweets and status updates) in the Notification Center, without using a separate client app.

WebOS, PlayBook OS, and Android 4 all do a form of it, so it makes sense OS X Mountain Lion does, too. "It" is providing visual navigation of open browser tabs. There's a new icon button in the Safari tabs bar that opens a scrolling list of browser tab previews that you can use to move among them. There's also a new gesture you can use on your touchpad or touch-savvy mouse to activate the tabs view.

Apple has long provided a guest account in OS X, so you can make sure the kids or babysitter aren't messing in your files, applications, and websites. OS X Mountain Lion provides a second guest option: You can have OS X Mountain Lion boot into a Safari-only mode, in which only Safari runs -- an isolated copy that stores nothing when it is quit.

You can't have both guest options active, though you can always create a limited standard account for trusted guests and use the Safari-only mode for everyone else.

It's a small thing, but a welcome one. Apps that implement OS X Mountain Lion's revised document APIs can have their documents be renamed in situ. No longer must you close the document to rename it in the Finder. Just click the document name in the title bar and enter the new name. That's it!

There are other controls available as well from the adjacent pop-up menu, but those were introduced in OS X Lion.

iOS on the iPad does it, and now so does OS X Mountain Lion: You can mirror your screen to a TV or projector via an Apple TV. The Displays system preference lets you control the resolution transmitted -- by default, your Mac's screen is adjusted to the TV screen, but you can override that, as well as have the Mac display resolution match the TV's.

You can set OS X Mountain Lion to autodetect an Apple TV on the network, in which case the Displays menu bar icon turns blue, giving you quick access when clicked to turning mirroring on or off.

I hate setting up Mail rules on multiple Macs -- there's no way to export or transfer them, so you have to reconstruct your rules on each Mac and keep them all updated. No longer: OS X Mountain Lion automatically syncs your Mail rules and other account settings across all Macs using the same iCloud ID (and running Mountain Lion). There's nothing to configure -- it just works. iOS 6 will support account syncing with both iOS devices and Macs as well.

The tech industry loves to gather our personal data, often unbeknownst to us. Apple gathers plenty of information about us in its stores, but in both iOS and OS X it provides strong controls to let us protect how our personal information is used by applications and Web services. The Security & Privacy system preference in OS X Mountain Lion adds to the location privacy settings in OS X Lion similar controls for access to your contacts, Twitter account, and Facebook account.

The first time an app or service wants access to these repositories, OS X displays an alert box asking you permission. If you say yes and later regret it, you can delete the untrusted app's or service's permissions in the system preference.

iOS's Notes app comes to OS X Mountain Lion -- notes are no longer handled in Mail. But notes remain server-based, so you can take notes and have them synced via iCloud, IMAP, and/or Exchange to iOS devices and Macs, as well as to other sever-based clients (such as Outlook) that support notes.

The Notes app in OS X Mountain Lion goes further than the one in iOS: You can drag in file attachments, for example, and you can peel off a note so that it stays onscreen even when Notes is closed -- a live sticky note, in effect.

Likewise, iOS's Reminders has come to OS X Mountain Lion. iCal (now called Calendar) used to manage to-do items, but no longer. Now it's Reminders' job. Reminders works like Notes in that it syncs its tasks via compatible servers to compatible apps on any platform.

But Reminders offers some special capabilities, such as location-based to-do items (for example, alerting you to get milk when you leave the office, or to pick up both kids when you arrive at the school).

Let's face it: iCal was never as sophisticated as the calendars in Outlook or Lotus Notes. OS X Mountain Lion's version of iCal -- renamed Calendar -- adds a calendar widget to make it easier to pick dates for your appointments, and its repeating-event capabilities now include options like the third Wednesday of the month. Parity at last!

Address Book is another OS X app that always felt awkwardly basic. In OS X Mountain Lion, the rechristened Contacts is less embarrassing. The interface is simplified, with a pane that you open up to work on groups rather than go through that weird modal switch used in previous versions.

Contacts is also better integrated with other services. It gains privacy management capabilities and integration with both Facebook and Twitter, as previously noted, as well as with Apple's Messages chat app.

Mission Control is one of those features users puzzle over, then one day get it. It lets you see all your open windows and spaces (collections of apps to help you organize a cluttered work environment) and navigate among them. It debuted in OS X Lion and shows the power of a touch interface, though it works well with a mouse, too.

In OS X Mountain Lion, there's one subtle but nice enhancement: In its system preference, you can have the Mission Control view show document windows for each app grouped with their app or have them presented independently of each other.

If you own an Apple TV, you've seen the really nice screen savers using images from Ken Burns, National Geographic, and others in a selection of moving displays. OS X Mountain Lion brings these screen savers to the Mac. OS X's traditional screen savers remain available, of course.

iOS 5 introduced the Game Center app last year, whch lets you track your scores and compare them to friends' performance using leaderboards and other "gamification" scoring mechanisms. Game Center comes to OS X Mountain Lion, so you can keep up on the competition when you've put your iPad, iPhone, or iPod Touch down.

And OS X's ancient Chess app is now Game Center-compatible, so you can compete over chess, too.

Here's one of those subtle changes Apple is famous for: When you copy or download a file, its icon has a progress bar so that you know how it's going.

That's more elegant than the floating Copy panel Apple has long used in OS X. But that Copy panel still appears when you copy multiple items, so you can see all their progress in one glance, as well as when a copy operation takes more than about 10 seconds. Still, if the Copy panel is obscured, you see the progress bar in your Finder window (and vice versa).

It seems obvious in retrospect: Mail has long let you search your mailboxes for text, names, and so on. But finding the relevant message is just the first step: Where is the text in the message itself?

OS X Mountain Lion lets you search the open message using the keyboard shortcut Command-F -- separately from using Mail's standard Search box to search your mailboxes. In other words, it now works the same way that Safari handles such inline searches.

OS X Mountain Lion centralizes all updates in the Mac App Store's Updates pane. When you do a Software Update from the Apple menu, the App Store opens and does the search -- not a separate app as before. That way, all your updates are in one place.

OS X Mountain Lion also now checks for app and system updates -- including security patches -- daily, rather than weekly. And you can no longer select that update schedule; it's daily or manual. OS X also now can be set to install security and system updates without asking (that's the default).

You can also have OS X automatically download any Mac apps purchased on another Mac using the same Apple ID -- just like how iOS works.

Apple's AirPrint technology to let iOS devices print wirelessly with no configuration hasn't taken off as you might have expected -- maybe people have discovered they need to print rarely when mobile.

But AirPrint printers are slowly finding their way into homes and workplaces, given that Hewlett-Packard and others include the technology in many models. OS X Mountain Lion now sees such printers when you add a printer in the Print & Scan system preference, and it gets and installs any drivers for you as well. Basically, it's now AirPrint-aware.

A long-standing Apple commitment has been to assistive technology for the disabled. OS X Mountain Lion refines the assistive features in what had been called the Universal Access system preference and is now called the Accessibility system preference. The system preference has been streamlined and better organized, and it's now more easily opened through the new shortcut Option-Command-F5.

Braille support has been expanded, modifier keys are now supported in VoiceOver drag and drop, and VoiceOver now supports item dragging into hotspots. Also, the Accessibility system preference now contains the speech-commands feature that had been in the Speech system preference but were displaced from there to make room for the new dictation capability covered earlier.